User's Manual

This output enables the transmitter synthesizer IC, U103 to receive data from the microprocessor. This pin
will change states when the transmitter synthesizer is to be loaded. This would occur just before the
Repeater is to transmit.
Pin 26 RX SYN EN
This output enables the receiver synthesizer IC, U102 to receive data from the microprocessor. This pin
will change states when the receive synthesizer is to be loaded. This would occur just after microprocessor
reset.
Pin 27 CLOCK
This output is the clock line from the microprocessor to the various peripherals in the Repeater, including
the memory IC and the synthesizer IC’s.
Pin 28 EEPROM DATA
This input/output is the data line to and from the memory IC, U309.
Pin 29 BEEP/ID TONE MSB
This output is the most significant bit of a two bit output for generating tones to be transmitted.
Pin 30 POWER LED
This active low output drives the power (green) front panel LED.
Pin 31 TX LED
This active low output drives the transmit (red) front panel LED.
Pins 32, 33 PROG
This input/output is used to communicate with the external programmer.
Pin 34 PROGRAM
This input puts the microcontroller into a special programming mode. Not used in all models.
Pins 35-38 Not Used
Pins 39, 40 Connected together, but not used
Pin 41 Not Used
Pins 42, 43 OSC1, OSC2
These two pins support the external crystal for generating the internal microprocessor clock.
Pin 44 Vdd
This is the 5-volt supply pin for the microprocessor. Normal voltage is 5 volts when powered up.